Exclude filter for load balancing switch

ABSTRACT

In an example, there is disclosed a computing apparatus for providing load-balanced switching, including a switching network; one or more logic elements operable for providing network switching or routing; and one or more logic elements providing a load balancing engine operable for: load balancing at least some incoming network traffic; receiving an exclude list identifying a network node excluded from load balancing; identifying a network packet directed to the network node excluded from load balancing; and directing the network packet to the network.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application62/141,726, filed Apr. 1, 2015, titled “ACCESS CONTROL LIST FOR A LOADBALANCER,” which is incorporated by reference in its entirety.

FIELD OF THE SPECIFICATION

This disclosure relates in general to the field of communications and,more particularly, to a system and method for providing automated policybased routing.

BACKGROUND

Data centers are increasingly used by enterprises for effectivecollaboration, data storage, and resource management. A typical datacenter network contains myriad network elements including servers, loadbalancers, routers, switches, etc. The network connecting the networkelements provides secure user access to data center services and aninfrastructure for deployment, interconnection, and aggregation ofshared resources. Improving operational efficiency and optimizingutilization of resources in data centers are some of the challengesfacing data center managers. Data center managers seek a resilientinfrastructure that consistently supports diverse applications andservices. A properly planned data center network provides applicationand data integrity and, further, optimizes application availability andperformance.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not necessarily drawn to scale, and are used forillustration purposes only. Where a scale is shown, explicitly orimplicitly, it provides only one illustrative example. In otherembodiments, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1A is a network level diagram of an enterprise computingenvironment according to one or more examples of the presentSpecification;

FIG. 1B is a more detailed view of a computing cluster according to oneor more examples of the present Specification;

FIG. 2A is a is a simplified schematic diagram illustrating a physicalview of a system for providing service appliances in a networkenvironment according to one or more examples of the presentSpecification;

FIG. 2B is a simplified schematic diagram illustrating a logical view ofthe system according to one or more examples of the presentSpecification;

FIG. 3 is a block diagram of a hardware element according to one or moreexamples of the present Specification;

FIG. 4 is a block diagram of a network topology according to one or moreexamples of the present Specification;

FIG. 5 is a block diagram of a state machine according to one or moreexamples of the present Specification.

FIG. 6 is a flow chart of a method according to one or more examples ofthe present Specification.

FIG. 7 is a block diagram of a TCAM load balancing chart;

FIG. 8 is a block diagram of selected elements of a network according toone or more examples of the present specification;

FIG. 9 is a flow chart of a method of adding an exclude filter accordingto one or more examples of the present specification; and

FIG. 10 is a flow chart of a method of handling traffic according to oneor more examples of the present specification.

SUMMARY

In an example, there is disclosed a computing apparatus for providingload-balanced switching, including a switching network; one or morelogic elements operable for providing network switching or routing; andone or more logic elements providing a load balancing engine operablefor: load balancing at least some incoming network traffic; receiving anexclude list identifying a network node excluded from load balancing;identifying a network packet directed to the network node excluded fromload balancing; and directing the network packet to the network.

EMBODIMENTS OF THE DISCLOSURE

In an example of a known computing system, a cluster of workload serversmay be provisioned, either as physical servers or as virtual machines,to provide a desired feature to end-users or clients. To provide justone nonlimiting example, the workload servers may provide a website.When a plurality of users make a large number of simultaneousconnections to the website, it is necessary to appropriately distributethe workload among the various servers in the server farm.

To this end, incoming traffic from client devices may be routed to anetwork switch. The network switch may then forward the traffic to aload balancer. An example of a commonly used load balancer is a networkappliance or virtual appliance running a Linux operating system andprovided with a full network stack, as well as load-balancing logic fordetermining which server to send the traffic to.

For example, a workload cluster may include 16 nodes, either physicalservers or virtual machines. The load balancer itself may also be eithera physical appliance or a virtual appliance. Upon receiving a packet,the load balancer determines the load on each of the 16 workloadservers. The load balancer then applies an algorithm to determine anappropriate node for handling the traffic. This may include, forexample, identifying a least burdened node and assigning the traffic tothat node. Each node may have its own IP address, which in oneembodiment is not exposed to end-user client devices. Rather, clientdevices are aware only of the IP address of the load balancer itself.Thus, the load balancer may modify the packet header, for example, byassigning it to the virtual IP (VIP) of one of the workload servers. Theload balancer may then return the packet to the switch, which routes thepacket to the appropriate workload server.

In this example, the incoming packet transfers from the switch to theload balancer, which may provide the full OSI 7 layer “stack” insoftware, operating on a full-featured operating system, such as Linux.Thus, the incoming packet is abstracted up to one of the upper layers ofthe OSI model, such as layer 6 or 7, so that it can be handled by theload-balancing software. The packet is then de-abstracted to a lowerlayer and returned to the switch, which forwards it to the appropriateworkload server. Upon receiving the packet, the workload server againabstracts the packet up to one of the higher levels of the OSI model.

The inventors of the present Specification have recognized that the loadbalancer, and its overhead, represent a potential bottleneck thatreduces the scalability of the network environment, and slows downhandling of network traffic. The process of passing the packet up anddown the OSI stack, in particular, while very fast from a human point ofview, can be a significant bottleneck from the point of view of anetwork.

However, the named inventors of the present Application have recognizedthat a network device, such as a switch or a router, can be configuredto natively act as a load balancer in addition to performing itsordinary network switching function. In that case, rather than provide aload-balancing algorithm in an application running on an operatingsystem, the switch may provide load-balancing via a much fastersolution, such as programmable hardware rather than a general purposesoftware-driven processor. This means that the load-balancing logic ishandled mostly or entirely at the hardware level. Furthermore, theswitch generally operates at lower levels of the OSI model, such aslayers 1 and 2. Thus, it has reduced overhead in abstracting andde-abstracting packets through the OSI stack.

Thus, the switch itself becomes the load balancer, and rather thanacting as a bottleneck, is capable of providing terabit-class bandwidthby operating at the hardware level.

In an example, a concept of traffic buckets and nodes is described.Traffic may be divided into “buckets.” Each bucket may be assigned to anode.

A traffic bucket serves as a classifier for identifying a subset oftraffic to be redirected. As many traffic buckets can be created asneeded for granularity. For bucketization of traffic, various L2/L3header fields can be used in the algorithm.

By selecting different fields, many buckets can be created. By way ofexample, we can use B0, B1, B2, B3, B4 . . . . Bn to designate trafficbuckets.

A traffic node serves as a “next-hop” for traffic forwarding. A node isan entity that has an associated IP address reachable from the switch.By way of example, we can use N0, N1, N2, N3 . . . Nm to designatenodes.

Mapping can be established to associate a traffic bucket to a node. Thisassociation creates a packet path for forwarding of traffic for eachbucket. This can include one-to-one mapping of a traffic bucket to anode, or many-to-one mapping of traffic buckets to a node (i.e.,multiple nodes may be assigned to a single node).

This architecture realizes substantial advantages over certain existingdeployments. For example, some existing load balancers suffer fromshortcomings such as inefficiency and expense. In one example, a lowcapacity load-balancer provides approximately 40 Gbps, while ahigher-end load balancer provides approximately 200 Gbps.

As discussed above, speed and scalability are enhanced by programmingthe load balancing engine in programmable hardware rather than insoftware running on a general-purpose processor programmed by software.Programmable hardware includes, for example, an application-specificintegrated circuit (ASIC), field-programmable gate array (FPGA),programmable logic array (PLA), or similar. Because the logic isimplemented directly in hardware, it can execute a “program” orders ofmagnitude faster than a CPU, which must fetch instructions from memory,and then run those instructions on general-purpose hardware.Furthermore, an operating system, multitasking, and multi-layer networkstack introduce additional complexity that does not contribute directlyto carrying out the load balancing function. In short, asoftware-programmable CPU is extremely versatile, and its function maybe easily adapted to many different tasks, but it is relatively slow. Adedicated programmable hardware device, programmed only for a singlefunction, is not versatile, but carries out its single, dedicatedfunction very quickly.

In one example, a hardware-based load balancer of the presentSpecification must be able to handle both traffic that is to be loadbalanced, and traffic that does not require load balancing. Fornon-load-balanced traffic, the device should still perform its nativefunction as a switch or router, and simply switch or route the trafficas appropriate.

To aid in this, and to preserve the speed advantage of the programmablehardware-based load balancing engine, it is advantageous not to storedata values in standard memories such as random access memories (RAM),as this could negate the speed advantages of the hardware. Rather, inone example, a ternary content-addressable memory (TCAM) is provided,and may be capable of operating at speeds approaching the speed of theprogrammable hardware itself. A content-addressable memory (CAM) is aspecies of memory used in extremely high-speed searches, such as thosenecessary for native terabit-class load balancing. CAM compares thesearch input (tag) to a table of stored data, and returns the address ofmatching datum. This is in contrast to RAM, in which the programprovides an address, and the RAM returns a value stored at that address.When a search is performed, if the CAM finds a match for the tag, theCAM returns the address of the tag, and optionally, the value of the tagas well. If the tag is not found, a “not found” value is returned. TCAMis a species of CAM, in which a tag can be searched not only for abinary “1” or “0,” but also for a ternary “X” (don't care). In otherwords, the search tag “110X” matches both “1101” and “1100.”

In the context of load balancing, a network administrator may configurea virtual IP (VIP) tag, including in one example an IP address,protocol, and port number. Entries may be made in the TCAM for VIP tagsthat are to be load balanced. Entries may also be made for a set ofnodes that can receive traffic matching that VIP tag.

The switch advertises the VIP tag via routing protocols, and receivestraffic destined for VIP. When traffic enters the switch or router, theVIP tag is checked against entries in the TCAM. If there is a matchingentry, the traffic is to be load balanced. The traffic is thenbucketized and load balanced to each node using TCAM entries.

This architecture realizes several important advantages. As servers movefrom 1 Gbps to 10 Gbps, traditional software load balancers have toscale appropriately. Load balancer appliances and service modules alsoconsume rack-space, power, wiring and cost. However, in an embodiment ofthe present Specification:

Every port of a switch or router can act as a load-balancer.

No external appliance and no service module are needed.

The teachings of this Specification can be used to provide terabit-classload balancing.

Furthermore, scalability is greatly enhanced. Many network switches havethe ability to modularly increase their size by adding on I/O modules.For example, a switch may have a baseline size of 48 ports, wherein eachport can be connected to one physical server appliance. The physicalserver appliance may be a standalone appliance providing the workloadservice, or may be a server configured to provide a hypervisor and tolaunch instances of virtual machines on demand. If the 48 ports on theswitch are exhausted, an additional I/O module, for example providing anadditional 48 ports, may be added onto the switch. Thus, the switch canbe scaled up to extremely large sizes with minimal configuration. Theswitch itself may be provided with a load-balancing engine, which inthis case may include dedicated hardware, firmware, or very low-levelsoftware such as BIOS to provide the load-balancing logic.

Exclude Filter for Load Balancing Switch

Certain co-pending patent applications describe how a network switch canbe configured with load-balancing capabilities, for example using a TCAMto significantly speed up load-balancing operations. While this hassubstantial benefits with respect to load-balancing speed, the switch ishandicapped if it is required to serve exclusively as a load balancer.Thus, in certain embodiments, several service nodes may be connected tothe switch in a service node cluster, and configured to handle aparticular class of traffic, which may be identified by a tuple ofdestination IP address, port, and protocol. The load-balancing switchmay include a virtual IP (VIP) that is used to identify a load balancedservice node cluster. Other nodes may be identified by their true IPaddresses.

It is also shown that the configuration of the present specification maybe flexible enough to permit attaching multiple service node clustersservicing different ports and protocols. Each may be identified with aseparate VIP to ensure that all traffic is properly load balanced anddelivered to the appropriate service nodes.

However, in certain cases there may be traffic that is not loadbalanced, and should not be directed to a service node cluster. In thiscase, one or more network endpoints may be designated as “excluded”nodes. Exclude nodes are not load balanced, and require no specialprocessing. Indeed, while an ordinary rule for the load-balancing switchincludes both a match and an action, the exclude rule or rules maycontain a match but no action. When an incoming packet matches theexclude rule, the switch may be configured to infer that the packet isforwarded to the destination IP address without performing anyload-balancing or special processing.

In an example, an exclude rule may be manually configured by a networkadministrator upon the addition of a device or virtual machine that isnot part of a load balanced service node cluster. In one example, andexclude rule is assigned to sequence 0. This ensures that the excluderule is process before every other rule.

A system and method for native load balancing on a switch will now bedescribed with more particular reference to the attached FIGURES.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. Further, the present disclosure mayrepeat reference numerals and/or letters in the various examples. Thisrepetition is for the purpose of simplicity and clarity and does not initself dictate a relationship between the various embodiments and/orconfigurations discussed. Different embodiments many have differentadvantages, and no particular advantage is necessarily required of anyembodiment.

In some embodiments, hyphenated reference numerals, such as 10-1 and10-2, may be used to refer to multiple instances of the same or asimilar item 10, or to different species of a genus 10.

FIG. 1A is a network-level diagram of a secured enterprise 100 accordingto one or more examples of the present Specification. In the example ofFIG. 1, a plurality of users 120 operates a plurality of client devices110. Specifically, user 120-1 operates desktop computer 110-1. User120-2 operates laptop computer 110-2. And user 120-3 operates mobiledevice 110-3.

Each computing device may include an appropriate operating system, suchas Microsoft Windows, Linux, Android, Mac OSX, Apple iOS, Unix, orsimilar. Some of the foregoing may be more often used on one type ofdevice than another. For example, desktop computer 110-1, which in oneembodiment may be an engineering workstation, may be more likely to useone of Microsoft Windows, Linux, Unix, or Mac OSX. Laptop computer110-2, which is usually a portable off-the-shelf device with fewercustomization options, may be more likely to run Microsoft Windows orMac OSX. Mobile device 110-3 may be more likely to run Android or iOS.However, these examples are not intended to be limiting.

Client devices 110 may be any suitable computing devices. In variousembodiments, a “computing device” may be or comprise, by way ofnon-limiting example, a computer, workstation, server, mainframe,embedded computer, embedded controller, embedded sensor, personaldigital assistant, laptop computer, cellular telephone, IP telephone,smart phone, tablet computer, convertible tablet computer, computingappliance, network appliance, receiver, wearable computer, handheldcalculator, virtual machine, virtual appliance, or any other electronic,microelectronic, or microelectromechanical device for processing andcommunicating data.

Client devices 110 may be communicatively coupled to one another and toother network resources via enterprise network 170. Enterprise network170 may be any suitable network or combination of one or more networksoperating on one or more suitable networking protocols, including forexample, a local area network, an intranet, a virtual network, a widearea network, a wireless network, a cellular network, or the Internet(optionally accessed via a proxy, virtual machine, or other similarsecurity mechanism) by way of nonlimiting example. Enterprise network170 may also include one or more servers, firewalls, routers, switches,security appliances, antivirus servers, or other useful network devices.In this illustration, enterprise network 170 is shown as a singlenetwork for simplicity, but in some embodiments, enterprise network 170may include a large number of networks, such as one or more enterpriseintranets connected to the Internet. Enterprise network 170 may alsoprovide access to an external network, such as the Internet, viaexternal network 172. External network 172 may similarly be any suitabletype of network.

A network administrator 150 may operate an administration console 140 toadminister a workload cluster 142 and to otherwise configure and enforceenterprise computing and security policies.

Enterprise 100 may encounter a variety of “network objects” on thenetwork. A network object may be any object that operates on orinteracts with enterprise network 170. In one example, objects may bebroadly divided into hardware objects, including any physical devicethat communicates with or operates via the network, and softwareobjects. Software objects may be further subdivided as “executableobjects” and “static objects.” Executable objects include any objectthat can actively execute code or operate autonomously, such asapplications, drivers, programs, executables, libraries, processes,runtimes, scripts, macros, binaries, interpreters, interpreted languagefiles, configuration files with inline code, embedded code, and firmwareinstructions by way of non-limiting example. A static object may bebroadly designated as any object that is not an executable object orthat cannot execute, such as documents, pictures, music files, textfiles, configuration files without inline code, videos, and drawings byway of non-limiting example. In some cases, hybrid software objects mayalso be provided, for example, a word processing document with built-inmacros or an animation with inline code. For security purposes, thesemay be considered as a separate class of software object, or may simplybe treated as executable objects.

Enterprise security policies may include authentication policies,network usage policies, network resource quotas, antivirus policies, andrestrictions on executable objects on client devices 110 by way ofnon-limiting example. Various network servers may provide substantiveservices such as routing, networking, enterprise data services, andenterprise applications.

Secure enterprise 100 may communicate across enterprise boundary 104with external network 172. Enterprise boundary 104 may represent aphysical, logical, or other boundary. External network 172 may include,for example, websites, servers, network protocols, and othernetwork-based services. In one example, a wireless base station 130, anexternal server 180, and an application repository 182 may be providedon external network 172, by way of nonlimiting example. Wireless basestation 130 may be, for example, an LTE base station or other similardevice that connects to mobile device 110-3 wirelessly. Wireless basestation 130 may in turn communicatively couple to external network 172.External server 180 may be a server that provides web pages, data, orother resources that enterprise users 120 may need to use.

Application repository 182 may represent a Windows or Apple “App Store”or update service, a Unix-like repository or ports collection, or othernetwork service providing users 120 the ability to interactively orautomatically download and install applications on client devices 110.In some cases, secured enterprise 100 may provide policy directives thatrestrict the types of applications that can be installed fromapplication repository 182. Thus, application repository 182 may includesoftware that is not malicious, but that is nevertheless against policy.For example, some enterprises restrict installation of entertainmentsoftware like media players and games. Thus, even a secure media playeror game may be unsuitable for an enterprise computer. Securityadministrator 150 may be responsible for distributing a computing policyconsistent with such restrictions and enforcing it on client devices120.

In another example, secured enterprise 100 may simply be a family, withparents assuming the role of security administrator 150. The parents maywish to protect their children from undesirable content, such aspornography, adware, spyware, age-inappropriate content, advocacy forcertain political, religious, or social movements, or forums fordiscussing illegal or dangerous activities, by way of non-limitingexample. In this case, the parent may perform some or all of the dutiesof security administrator 150.

FIG. 1B is a block diagram disclosing a workload cluster 142 accordingto one or more examples of the present Specification. In this example,workload cluster 142 includes a rack mount chassis 144 which hasinstalled therein a plurality of rack mount servers 146-1 through 146-N.Each rack mount server 146 may be a dedicated appliance, or may beconfigured with a hypervisor to launch one or more instances of avirtual client.

A switch 190 may be provided to communicatively couple workload cluster142 to enterprise network 170. As described below, switch 190 may have anumber of physical ports for communicatively coupling to rack mountservers 146. In an example, each server 146 has a physical wiredconnection, such as an Ethernet connection, to a single port of switch190.

In some cases, some or all of rack mount servers 146-1 through 146-N arededicated to providing a microcloud 160. Microcloud 160 may be a singlepurpose or dedicated cloud providing a particular service. For example,microcloud 160 may be configured to serve a website, providecommunication systems such as one or more 4G LTE services, or any otherappropriate service. In some cases, microcloud 160 is provided as a“tenant” on workload cluster 142. Workload cluster 142 may provide avirtual environment manager 164, which may be responsible for enforcingtenant boundaries between one or more microcloud tenants 160, and fordynamically provisioning virtual machines 162 as necessary. Virtualmachines 162-1 through 162-N may represent a plurality of instances of avirtual server appliance. In some cases, VMs 162 may also be provided indifferent flavors. For example, some VMs 162 may be provisioned asfirewalls, others may be provisioned as antivirus scanning appliance,and yet others may provide other auxiliary functions, in addition to VMs162 provisioned as workload servers.

When switch 190 is provisioned with a load-balancing engine, theload-balancing engine is responsible for keeping track of the number andvirtual IP (VIP) of workload servers, so that it can properly routetraffic to the workload servers. In the case where each rack mountserver 146 is a standalone appliance, switch 190 may maintain a table ofthe VIP of each rack mount server 146. In cases where workload serversare provided in a microcloud 160, switch 190 may provide a table thatmaps the VIP of each VM to a VIP assigned to the physical rack mountserver 146 on which that VM 162 resides. Thus, switch 190 may includelogic not only for routing the packet to the correct rack mount server146, but also for directing the packet to the correct VM 162 on thatrack mount server 146.

FIGS. 2A and 2B show examples of a system architecture for providingservice appliances in a network environment, and specifically, providingservice appliances as virtual line cards in a network switch. Thevirtual line card allows the service appliances to be located anywherein the network, but other ways of providing the service appliance (e.g.,directly connecting the service appliance on the switch) are alsopossible. It is noted that the examples are merely illustrative and arenot intended to be limiting. Other architectures and configurations areenvisioned by the disclosure.

FIG. 2A is a simplified schematic diagram illustrating a physical viewof a system 110 for providing service appliances in a networkenvironment. FIG. 2A includes a network (illustrated as multiple links212) that connects one or more server farms 142-1 and 142-2 to one ormore clients 110 via a cloud 210. Cloud 210 may encompass any public,semi-public, and/or private networks including enterprise networks, anInternet or intranet, community networks, etc. Individual servers inserver farm 142-1 and 142-2 may communicate within the same farm viaswitches 240-1 and 240-2, respectively. Servers in server farm 142-1 maycommunicate with servers in server farm 142-2 via a switch 190 in thisparticular example implementation.

A service appliance 224 may connect to switch 190 over a communicationchannel 226 (e.g., over a port-channel). As used herein, a“communication channel” encompasses a physical transmission medium(e.g., a wire), or a logical connection (e.g., a radio channel, anetwork connection) used to convey information signals (e.g., datapackets, control packets, etc.) from one or more senders (e.g., switch190) to one or more receivers (e.g., service appliance 224). Acommunication channel, as used herein, can include one or morecommunication links, which may be physical (e.g., wire) or logical(e.g., data link, wireless link, etc.). Termination points ofcommunication channels can include interfaces such as Ethernet ports,serial ports, etc. In embodiments of system 110, communication channel326 may be a single channel: deployed for both control messages (i.e.,messages that include control packets) and data messages (i.e., messagesthat include data packets).

As used herein, a “service appliance” is a discrete (and generallyseparate) hardware device or virtual machine with integrated software(e.g., firmware), designed to provide one or more network servicesincluding load balancing, firewall, intrusion prevention, virtualprivate network (VPN), proxy, etc. In some cases, switch 190 may beconfigured with an intelligent service card manager module (ISCM) 220,and service appliance 224 may be configured with a correspondingintelligent service card client module (ISCC) 230. ISCM 220 and ISCC 230can form part of a Remote Integrated Service Engine (RISE)infrastructure for configuring service appliance 224 on the switch,e.g., as a virtual line card in switch 190.

FIG. 2B is a simplified schematic diagram illustrating a logical view ofsystem 110. In some cases, ISCC 230 and ISCM 220 may be configured toallow service appliance 224 to appear as a virtual line card 290, orsome other virtual network node/entity. The terms “line card” and“service module” are interchangeably used herein to refer to modularelectronic circuits interfacing with telecommunication lines (such ascopper wires or optical fibers) and that offer a pathway to the rest ofa telecommunications network. Service appliance is often referred simplyas “appliance” or “module” herein. Hence, virtual line card 290 isinterchangeable (in certain instances) with ISCM 220. A virtual servicemodule (or a virtual line card) is a logical instance (of a servicemodule) providing the same functionalities (as the service module).Service modules may perform various functions including providingnetwork services (e.g., similar to service appliances). One differencebetween a service module and a service appliance is that the servicemodule is physically located within a switch, for example, on anappropriate slot. Virtual service modules are similarly configurablewithin a switch.

In an example, RISE (or comparable technologies) allows (external)service appliances connect to a switch and behave like a service modulewithin a switch without having to take up a physical slot in the switch.RISE helps consolidate how the appliances are provisioned, and enablesthe appliances to have the benefits of being a service module within theswitch. The task for provisioning and configuring of these serviceappliances is performed mostly by RISE being provided on the switch,making it easy for network administrators to add/remove serviceappliances in the network.

According to embodiments of the present disclosure, an appliance usercan enjoy the same benefit of a service module's simple configurationand operation using the infrastructure of system 110. For example,setting up service appliance 224 for network configurations may beunnecessary. Substantially all such configurations may be made viaswitch 190, instead of service appliance 224. Service appliance 224 mayoffload (i.e., transfer) any network (e.g., L2/L3 network) specificcontrol plane and data plane operations to switch 190. Data pathacceleration that leverages an application specific integrated circuit(ASIC) (potentially embedded in switch 190) may also be possible invarious embodiments. Switch 190 may communicate control messages toservice appliance 224 over communication channel 326. Thus,configuration and provisioning of services within service appliance 224may be implemented via switch 190.

Note that the numerical and letter designations assigned to the elementsof FIGS. 2A and 2B do not connote any type of hierarchy; thedesignations are arbitrary and have been used for purposes of teachingonly. Such designations should not be construed in any way to limittheir capabilities, functionalities, or applications in the potentialenvironments that may benefit from the features of system 110. For easeof description, only two representative server farms are illustrated inFIGS. 2A and 2B. Any number of server farms and switches may beconnected in the network without departing from the broad scope of thepresent disclosure.

For purposes of illustrating the techniques of system 110, it isimportant to understand the communications in a given system such as thesystem shown in FIGS. 2A and 2B. The following foundational informationmay be viewed as a basis from which the present disclosure may beproperly explained. Such information is offered earnestly for purposesof explanation only and, accordingly, should not be construed in any wayto limit the broad scope of the present disclosure and its potentialapplications.

Typically, network services such as load balancing, firewall, intrusionprevention, proxy, virtual private network (VPN), etc. are providedthrough one or more of the following options: (1) service appliancesthat connect to network switches and routers; (2) specially designedhigh-performance routers configured with the services; or (3) networkdevices such as routers or switches that are configured with servicemodules that provide the services.

Some service appliances (e.g., load balancers) integrate services suchas load balancing, firewall, intrusion prevention, VPN, etc. in a singlebox format, which is generally based on modular, scalable platforms andwhich provides a cost-effective option of the three options listedpreviously. Service appliances may be connected externally to a switch(e.g., aggregate switch or access switch, etc.) via appropriate ports.Different service appliances are designed with specific featuresapplicable to different network environments. The service appliances maybe deployed independently to service-specific areas of the networkinfrastructure, or they may be combined for a layered approach. Serviceappliances are typically located between the clients and server farms.Data packets generally pass through the service appliances on the way to(and from) the servers/clients. The service appliances may be managed bya management application (e.g., software) on the service appliance thatenables configuration settings and other management functions.

Specially designed high-performance routers may also provide networkservices. Such routers may implement a massive parallel processorhardware and software architecture to deliver integrated networkservices (e.g., firewall, deep packet inspection, etc.). Many of thefunctionalities are embedded in a specially designed processor in therouter. For example, such a specially designed router can provide anintegrated security solution (e.g., stateful packet filtering, intrusiondetection and prevention, per-user authentication and authorization, VPNcapability, extensive QoS mechanisms, multiprotocol routing, voiceapplication support, and integrated WAN interface support) and routingin a single box.

Network services may also be integrated into a network device (such as aswitch or router) using dedicated line cards. The line cards may beinstalled inside the device, allowing any port on the device to operateas a firewall port, while integrating the services inside the networkinfrastructure. Several line cards may be installed in the same chassis,providing a modular solution where needed. Such solutions permit theuser to take advantage of existing switching and routing infrastructurewithout any costly upgrades.

Turning to the potential infrastructure of FIGS. 2A and 2B, the examplenetwork environment may be configured as one or more networks and,further, may be configured in any form including, but not limited to,local area networks (LANs), wireless local area networks (WLANs),virtual local area networks (VLANs), metropolitan area networks (MANs),wide area networks (WANs), VPNs, Intranet, Extranet, any otherappropriate architecture or system, or any combination thereof thatfacilitates communications in a network. In some embodiments, acommunication link may represent any electronic link supporting a LANenvironment such as, for example, cable, Ethernet, wireless technologies(e.g., IEEE 802.11x), ATM, fiber optics, etc. or any suitablecombination thereof. In other embodiments, communication links mayrepresent a remote connection through any appropriate medium (e.g.,digital subscriber lines (DSL), telephone lines, T1 lines, T3 lines,wireless, satellite, fiber optics, cable, Ethernet, etc. or anycombination thereof) and/or through any additional networks such as awide area networks (e.g., the Internet).

Elements of FIGS. 2A and 2B may be coupled to one another through one ormore interfaces employing any suitable connection (wired or wireless),which provides a viable pathway for electronic communications.Additionally, any one or more of these elements may be combined orremoved from the architecture based on particular configuration needs.System 110 may include a configuration capable of transmission controlprotocol/Internet protocol (TCP/IP) communications for the electronictransmission or reception of packets in a network. System 110 may alsooperate in conjunction with a user datagram protocol/IP (UDP/IP) or anyother suitable protocol, where appropriate and based on particularneeds. In addition, gateways, routers, switches, and any other suitablenetwork elements may be used to facilitate electronic communicationbetween various nodes in the network.

Switches in system 110, including switches 190, 240-1, and 240-2, mayinclude any type of network element connecting network segments. Forexample, switches 190, 240-1, and 240-2 may include a multi-port networkbridge that processes and routes data at a data link layer (Layer 2). Inanother example, switches 190, 240-1, and 240-2 may process data at anetwork layer (Layer 3), or Layer 4 (with network address translationand load distribution), or Layer 7 (load distribution based onapplication specific transactions), or at multiple layers (e.g., Layer 2and Layer 3). In certain embodiments, functionalities of switches 190,240-1, and 240-2 may be integrated into other network devices such asgateways, routers, or servers. In various embodiments, switches 190,240-1, and 240-2 may be managed switches (e.g., managed using a commandline interface (CLI), a web interface, etc.).

Communication channel 226 may include a port-channel, which canencompass an aggregation of multiple physical interfaces into onelogical interface, for example, to provide higher aggregated bandwidth,load balancing and link redundancy. Communication channel 226 withmultiple links can provide a high availability channel: if one linkfails, traffic previously carried on this link can be switched to theremaining links. Communication channel 226 may contain up to 16 physicalcommunication links and may span multiple modules for added highavailability. In one embodiment, communication channel 226 can representa port-channel with an aggregation of four point-to-point communicationlinks over multiple ports. In another embodiment, communication channel226 can represent a virtual port-channel (vPC).

Although FIGS. 2A and 2B show server farms 142-1 and 142-2, it should beappreciated that system 110 is not limited to servers. In fact, anynetwork element may be connected to the network via appropriateswitches, where these implementations may be based on particular needs.As used herein, the term “network element” is meant to encompasscomputers, virtual machines, network appliances, servers, routers,switches, gateways, bridges, load balancers, firewalls, processors,modules, or any other suitable device, component, proprietary element,or object operable to exchange information in a network environment.Moreover, the network elements may include any suitable hardware,software, components, modules, interfaces, or objects that facilitatethe operations thereof. This may be inclusive of appropriate algorithmsand communication protocols that allow for the effective exchange ofdata or information. For example, server farms 142-1 and 142-2 may bereplaced with LANs connecting desktop computers in a small office. Inanother example, server farms 142-1 and 142-2 may be replaced with anetwork of wireless communication devices. In yet another example,server farms 142-1 and 142-2 may be replaced with one or moresupercomputers. Various other configurations and devices arecontemplated within the broad framework of the present disclosure.

According to embodiments of the present disclosure, system 110 mayprovide for a fabric extender (FEX)-like protocol, auto-discovery,message transport service (MTS)-like control messages, and definedmessages between service appliance 224 and switch 190. Configuration ofservice appliance 224 may be performed on switch 190 as for a line card.Data path forwarding may be offloaded to network line cards in switch190. Control path processing may be offloaded to a supervisor engine onswitch 190 as appropriate. In embodiments where service appliance 224has multiple virtual services (e.g., virtual machines), each virtualservice may be a separate virtual line card on switch 190.

FIG. 3 is a simplified block diagram illustrating example details ofsystem 110 according to embodiments of the present disclosure. Asupervisor engine 360 on switch 190 may communicate with serviceappliance 224 via a line card including a fabric port 362 that connectspoint-to-point to a node on service appliance 224. Supervisor engine 360may include several modules such as an installer 364, an Ethernet portmanager (ethPM) 366, a port-channel manager (PCM) 368, a Quality ofService (QoS) element 370, a route policy manager (RPM) 372, aunified/unicast routing information base (URIB) 374, an access controllist manager (ACLmgr) 376, and a service policy manager (SPM) 378 forperforming various routing and/or management functions. ISCM 220 may beprovisioned in supervisor engine 360 to provide RISE relatedfunctionalities. ISCM 220 may manage one or more service modules,including in-chassis service modules and remote service modules.

In various embodiments, service appliance 224 may support stream controltransmission protocol (SCTP) with various addresses (e.g., 127addresses). In the absence of native SCTP support in supervisor engine360, tunneling over UDP may be enforced to send SCTP packets. A Netstackmodule 380 may be provisioned in supervisor engine 360 for implementingTCP/IP stack for received frames hitting the control-plane of supervisorengine 360. Supervisor engine 360 may be configured with an inband port352, which may be a virtual port that provides an interface formanagement traffic (such as auto-discovery) to a management processorsuch as a processor 386.

Each logical block disclosed herein is broadly intended to include oneor more logic elements configured and operable for providing thedisclosed logical operation of that block. As used throughout thisSpecification, “logic elements” may include hardware, external hardware(digital, analog, or mixed-signal), software, reciprocating software,services, drivers, interfaces, components, modules, algorithms, sensors,components, firmware, microcode, programmable logic, or objects that cancoordinate to achieve a logical operation.

In various examples, a “processor” may include any combination of logicelements, including by way of non-limiting example a microprocessor,digital signal processor, field-programmable gate array, graphicsprocessing unit, programmable logic array, application-specificintegrated circuit, or virtual machine processor. In certainarchitectures, a multi-core processor may be provided, in which caseprocessor 386 may be treated as only one core of a multi-core processor,or may be treated as the entire multi-core processor, as appropriate. Insome embodiments, one or more co-processor may also be provided forspecialized or support functions. In some examples, the processor is aprogrammable hardware device, which in this Specification expresslyexcludes a general-purpose CPU.

Load balancing engine 320, in one example, is operable to carry outcomputer-implemented methods as described in this Specification. Loadbalancing engine 320 may include one or more processors, and one or morenon-transitory computer-readable mediums having stored thereonexecutable instructions operable to instruct a processor to provide loadbalancing. As used throughout this Specification, an “engine” includesany combination of one or more logic elements, of similar or dissimilarspecies, operable for and configured to perform one or more methodsprovided by load balancing engine 320. Thus, load balancing engine 320may comprise one or more logic elements configured to provide methods asdisclosed in this Specification. In some cases, load balancing engine320 may include a special integrated circuit designed to carry out amethod or a part thereof, and may also include software instructionsoperable to instruct a processor to perform the method. In some cases,load balancing engine 320 may run as a “daemon” process. A “daemon” mayinclude any program or series of executable instructions, whetherimplemented in hardware, software, firmware, or any combination thereof,that runs as a background process, a terminate-and-stay-residentprogram, a service, system extension, control panel, bootup procedure,BIOS subroutine, or any similar program that operates without directuser interaction. In certain embodiments, daemon processes may run withelevated privileges in a “driver space,” or in ring 0, 1, or 2 in aprotection ring architecture. It should also be noted that loadbalancing engine 320 may also include other hardware and software,including configuration files, registry entries, and interactive oruser-mode software by way of non-limiting example.

In one example, load balancing engine 320 includes executableinstructions stored on a non-transitory medium operable to perform amethod according to this Specification. At an appropriate time, such asupon booting the device or upon a command from the operating system or auser, load balancing engine 320 may retrieve a copy of software fromstorage and load it into memory. The processor may then iterativelyexecute the instructions of load balancing engine 320 to provide thedesired method.

In another example, load balancing engine 320 includes logic executed onan ASIC, FPGA, or other low-level hardware device specificallyprogrammed to carry out the functions of load balancing engine 320. Inone case, any portions of load balancing engine 320 that are nothard-coded into the logic may be loaded from a firmware or similarmemory. In this case, load-balancing engine 320 may operate without thebenefit of an operating system, to improve speed and efficiency.

Load balancing engine 320 may also communicatively couple to a TCAM 329.TCAM 329 may be configured to provide high-speed searching as disclosedherein.

According to various embodiments, ISCM 220 may offer variousfunctionalities such as handling (i.e., accommodating, managing,processing, etc.) RISE messages (e.g., in MTS format), high availabilityactivities, timer events, packet switch stream (PSS), American StandardCode for Information Interchange (ASCII) generation, logging, eventhandling, health monitoring, debugging, etc. ISCM 220 may be a finitestate machine utility (FSMU) based application (e.g., which indicates anabstract machine that can be in one of a finite number of states). Invarious embodiments, ISCM 220 may have a well-defined MTS seamlessauthentication protocol (MTS SAP) assigned and it can open asocket-based MTS queue and bind to the well-defined SAP such that otherprocesses may communicate with it.

In various embodiments, ISCM 220 may also maintain an array of MTSoperation code (“opcode”), which can define how to process a receivedMTS message. The array may include per-opcode specific MTS flags,handler functions, etc. ISCM 220 may be configured to receive CLI drivenMTS messages, MTS notifications (such as event driven messagesindicating, for example, that a particular VLAN is up or down), and MTSrequest/responses. In various embodiments, ISCM 220 may be configured sothat MTS-based communication with other processes may be non-blockingand asynchronous. Thus, ISCM 220 may handle multiple events (which canarrive at any time) for the same resource such that the state of theresource is consistent (and not compromised). A similar opcode can beprovided even in non-MTS messages, which serves to indicate how to aswitch or a service can process the message.

After ports (e.g., appliance ports and switch ports) have beenconfigured in RISE mode, ISCM 220 and ISCC 230 may performauto-discovery and bootstrap to establish an appropriate controlchannel. After the control channel is established, applications inservice appliance 224 may send control messages (e.g., using the UDPsocket interface) to ISCC 230 through an application control plane 384.Application control plane 384 generally encompasses one or more softwarecomponents for performing workflow management, self-management, andother application control layer processes. ISCC 230 may forward thecontrol messages to ISCM 220 of switch 190 over communication channel326. In example embodiments, ISCM 220 and ISCC 230 may communicate viaUDP packets; however, various other protocols and formats may beaccommodated by the teachings of the present disclosure. Supervisor 360may be provisioned with (or have access to) processor 386 and a memory388 for performing its various functions. ISCM 220 may use processor 386and memory 388 to perform RISE related functions in switch 190.Similarly, service appliance 224 may be provisioned with (or have accessto) a processor 390 and a memory 392. ISCC 230 may use processor 390 andmemory 392 to perform RISE related functions in service appliance 224.

FIG. 4 is a block diagram of a routing table 400 according to one ormore examples of the present Specification. In this example, four nodesare provided, designated node NO, N1, N2, and N3. Each node represents aserver appliance having a unique VIP, whether a dedicated hardwareserver appliance or a virtual server appliance.

Load-balancing engine 320 designates 8 traffic buckets, labeled B0, B1,B2, B3, B4, B5, B6, and B7. Based on load and demand, load-balancingengine 320 maps each traffic bucket to an appropriate node. In thisexample, buckets B0 and B4 are mapped to node NO. Buckets B1 and B5 aremapped to node N1. Buckets B2 and B6 are mapped to node N2. Buckets B3and B7 are mapped to node N3. These mappings are provided by way ofnonlimiting example only, and are provided strictly to illustrate theprinciple of mapping buckets to nodes.

When switch 190 receives incoming traffic, load-balancing engine 320operates to execute an appropriate algorithm for assigning the incomingtraffic to a traffic bucket. This may include, for example, random orpseudorandom assignment, round robin scheduling, or any suitablescheduling algorithm. In one example, an algorithm may be based on thesource IP address of the incoming packet, as described in more detail inconnection with FIGS. 7 and 8.

After assigning the traffic to a bucket, switch 194 modifies the packetwith the appropriate VIP for the node servicing that bucket, andforwards the packet.

When a response comes, switch 190 modifies the packet to reflect thepublically visible IP address of switch 190, so that the load balancingis completely invisible to external hosts.

FIG. 5 is a flowchart of an example method 500 performed byload-balancing engine 320 according to one or more examples of thepresent Specification.

In block 510, switch 190 receives incoming traffic and provides theincoming traffic to load-balancing engine 320.

In block 520, switch 190 compares the destination IP of the incomingtraffic to the VIP designated for load balancing. If there is a match,the incoming traffic is provided to load balancing engine 320 for loadbalancing. If not, then switch 190 simply routes or switches the trafficaccording to its normal function.

In block 530, load-balancing engine 320 assesses workload balance foravailable workload servers. As described above, this may be performedvia round-robin assignment, random or pseudo-random assignment, or anyother suitable load balancing algorithm.

In block 540, load-balancing engine 320 identifies the best availablenode for servicing the incoming traffic, based on the assessing of block530.

In block 550, according to the identifying of block 540, load-balancingengine 320 assigns the incoming traffic to a bucket for associated withthe best available node. Assigning to a node may comprise modifying theheader to reflect the VIP for the assigned node.

In block 570, after load-balancing engine 320 has assigned the trafficto an appropriate bucket and thereby to an appropriate node, switch 190forwards the incoming traffic to the node designated for servicing thatbucket, specifically by forwarding the traffic to the appropriate VIP.

In block 580, load-balancing engine 320 may log the transaction, asappropriate or necessary.

In block 590, the method is done.

FIG. 6 illustrates a method of performing load balancing on a switchwith the aid of a TCAM, such as TCAM 329 according to one or moreexamples of the present Specification. This example employs the notionof a flow. In an example, a flow is uniquely identified by a tuple T,comprising src-ip (source IP address), dst-ip (destination IP address),protocol, L4-src-port (layer 4 source port) and L4-dst-port (layer 4destination port).

In an example, a client device 110-1 sends a packet directed to a VIPserviced by switch 190. By way of illustration, this flow is referred toas F1, and tuple T1 identifies flow F1. Tuple T1 comprises(Dev-110-1-IP, VIP, TCP, L4-src-port, L4-dest-port).

Similarly client device 110-2 initiates traffic to the same VIP. Sinceclient 110-2's IP address is different from client 110-1's, this flowwill have a different Tuple. By way of illustration, this is referred toas flow F2, identified by tuple T2. Tuple T2 comprises (Dev-110-2-IP,VIP, TCP, L4-src-port, L4-dest-port).

In various examples, sets of buckets may be part of a “pool,” and one ormore pools can be assigned to a single VIP, allowing VIP traffic to beload balanced among server nodes.

Referring now to method 600 in FIG. 6, it is assumed that switch 190 hasnow received flows F1 and F2.

In block 610, TCAM 329 looks up the IP address of VIP as it appears inboth flows. In this example, both flows are directed to VIP, which is avirtual IP address for a service provided by servers in workload cluster142. Thus, switch 190 can quickly determine that flows F1 and F2 are tobe load balanced.

In block 620, load balancing engine 320 assigns each node to a trafficbucket as described herein. In certain examples, this may beaccomplished by any of the load balancing algorithms disclosed herein,or by any other appropriate load balancing algorithm. In one example,assigning each flow to a bucket comprises assigning according to method900 of FIG. 9, based on Dev-110-1-IP and Dev-110-2-IP respectively. Inthat case, TCAM 329 may include a table mapping masked IP addressfragments to traffic buckets.

In block 640, load balancing engine 320 assigns each flow to a node forservicing, such as a workload server in workload cluster 142. This maybe a deterministic assignment based on the traffic bucket that each flowwas assigned to. For increased speed, this may also be performed usingTCAM 329. For example, TCAM 329 may include a table mapping trafficbuckets to service nodes.

In block 660, load balancing engine 320 rewrites the L2 header for theincoming packets. For example, assuming that flow F1 was assigned toservice node 1 in workload cluster 142, and flow F2 was assigned toservice node 2 in workload cluster 142, load balancing engine 320rewrites the L2 headers for the packets in those flows to direct them totheir respective service nodes.

In block 680, switch 190 is finished with its load balancing tasks, andnow acts as a switch, switching or routing the packets to the nodesprovided by their new L2 headers.

Blocks 610 through 680 are repeated for each incoming packet, with anappropriate bucket and service node being selected for each. Assuming awell-configured load balancing engine 320, packets will be welldistributed across available service nodes in workload cluster 142 sothat workload is optimally distributed across available service nodes.

Reverse traffic (response from service nodes to client devices) aredelivered directly to the respective clients without any interventionfrom load balancing engine 320.

FIG. 7 is a block diagram view 700 of method 600 as described in FIG. 6.

FIG. 8 is a block diagram of selected aspects of the network accordingto one or more examples of the present specification. Load-balancingswitch 190 may be configured to provide both traditional switchingservices and load-balancing services. In this example, several servicenodes comprise a service node cluster 820 with VIP 192.168.1.40 thatwill handle a particular class of network traffic. In this example, theservice nodes of cluster 820 include nodes S0, S1, S2, and S3. Each ofthese may be a substantial clone of the other, and each may beconfigured to provide identical or similar services. By way of example,node S0 has IP address 192.168.1.12. Node S1 has IP address192.168.1.14. Node S2 has IP address 192.168.1.16. Node S3 has IPaddress 192.168.1.20. A routing table, such as table 400 of FIG. 4, maybe used to assign various traffic buckets to the nodes.

The network also includes excluded node E0 at IP address 192.168.1.24.Node E0 is not part of the service node cluster. For any suitablepurpose, node E0 is however connected to load-balancing switch 190 alongwith the service nodes.

Thus, when client 110 directs traffic to switch 190, it is necessary forload-balancing switch 190 to decide whether the traffic is to bedirected to service node cluster 820, or to exclude node E0. Thus, aspecial rule at sequence 0 may be used to match node E0.

FIG. 9 is a flowchart of an example method according to one or moreexamples of the present specification. This method discloses inparticular a network administrator 150 adding an excluded node to thenetwork, and properly configuring the network.

In block 900, exclude node E0 is added to the network. This may be byphysically connecting the device to the network, or by provisioning anew virtual machine, by way of nonlimiting example.

In block 920, administrator 150 may manually create an ACL specifyingthe type of traffic to be excluded from redirection. This may include,for example, a tuple including an IP address, port, and protocol. Anexample command-line interface for accomplishing this may includecommands such as the following:

-   switch(config)# sh run services-   !Command: show running-config services-   !Time: Sun Dec 4 12:13:51 2011-   version 6.2(10)-   feature itd-   itd device-group 1 node ip 1.1.1.10-   itd test

In block 940, administrator 150 adds the new ACL to the ITD service. Thecommand “itd test” creates a new ITD service named “test.” Any suitableservice name may be used.

-   device-group 1-   ingress interface Eth2/7-   exclude access-list test_itd_deny_acl

The “exclude” command instructs ITD to create an entry to exclude theaccess list “test_itd_deny_acl.”

-   no shut-   ip access-list test_itd_deny_acl-   60 permit ip any 3.3.3.10/32

This command creates a rule for matching the manually created ACL. Inthis case, any IP matching 3.3.3.10/32, with any service, matches. Thisassociates the manually-created ACL with the service.

-   switch(config)# sh run rpm-   !Command: show running-config rpm-   !Time: Sun Dec 4 12:15:00 2011-   version 6.2(10)-   feature pbr-   route-map test_itd_pool pbr-statistics-   route-map test_itd_pool deny 0

This command matches the user-created ACL. By way of example, theexclude ACL is set to sequence 0, to ensure that it is always evaluatedfirst.

-   description auto generated route-map for ITD service test-   match ip address test_itd_deny_acl route-map test_itd_pool permit 1-   description auto generated route-map for ITD service test match ip    address test_itd_bucket_1-   set ip next-hop 1.1.1.10

All ACLS other than the exclude ACL are set to sequence 1 or higher,thus ensuring that they are evaluated after the exclude ACL.

-   interface Ethernet2/7-   ip policy route-map test_itd_pool-   ---------------

An example hardware entry is shown below:

-   Tcam 1 resource usage:-   ---------------------- Label_b=0x802-   Bank 0-   -------   IPv4 Class-   Policies: PBR(test_itd_bucket_1) Netflow profile: 0-   Netflow deny profile: 0-   Entries:-   [Index] Entry [Stats]-   ----------------------   [000e:0007:0007] prec 1 permit-routed ip 0.0.0.0/0 224.0.0.0/4 [0]    [0008:0008:0008] prec 1 permit-routed ip 3.3.3.10/32 0.0.0.0/0 [0]    [0009:0009:0009] prec 1 permit-routed ip 3.3.3.1/32 0.0.0.0/0 [0]    [000a:000a:000a] prec 1 permit-routed ip 0.0.0.0/0 3.3.3.10/32 [0]    [000b:000d:000d] prec 1 redirect(0xa03d)-routed ip 0.0.0.0/0    0.0.0.0/0 [0] [0010:000f:000f] prec 1 permit-routed ip 0.0.0.0/0    0.0.0.0/0 [0]

In block 960, responsive at least in part to the administrator addingthe ACL to the ITD service, the ITD load-balancing engine (or a userinterface portion thereof) creates a “deny” route map sequence and addsthis to the service map, with sequence 0. This ensures that the newroute map is always the first to be considered for matching against thenew packet. This ensures that excluded packets are forwarded from theswitch 190 before any load-balancing can take place.

In block 970, the load-balancing engine adds any load balanced ACLs to asequence number greater than or equal to 1. Again, this is to ensurethat the deny sequence has priority over all other sequences.

In block 990, the method is done.

FIG. 10 is a flowchart of a method of load-balancing traffic accordingto one or more examples of the present specification.

In block 1000, load-balancing network switch 190 receives an incomingpacket.

In block 1020, load-balancing engine 320 inspects the packet, andextracts relevant data, such as the destination IP address, port, andprotocol.

In decision block 1040, load-balancing engine 320 determines whether theincoming packet matches sequence 0, the exclude sequence.

If not, then in block 1080, load-balancing engine 320 performs itsordinary load-balancing work. In block 1090, the method is done.

Returning to decision block 1040, if the incoming packet matches rule 0,the exclude filter, then in block 1070, switch 190 directly forwards thepacket to its destination, with no load-balancing and no redirection. Inblock 1090, the method is done.

In other embodiments, the “exclude list” may in fact be a whitelist ofload balanced traffic. In that case, only traffic on the whitelist isload balanced. Excluded packets and nodes are thus implicitly identifiedin the exclude list by not being included in the whitelist. It shouldalso be noted that in some embodiments, multiple exclude lists may beprovided, in which case traffic identified in any exclude list is notload balanced.

By way of example, there is disclosed a computing apparatus forproviding load-balanced switching, comprising: a switching network; oneor more logic elements operable for providing network switching orrouting; and one or more logic elements comprising a load balancingengine operable for: load balancing at least some incoming networktraffic; receiving an exclude list identifying a network node excludedfrom load balancing; identifying a network packet directed to thenetwork node excluded from load balancing; and directing the networkpacket to the network node excluded from load balancing withoutperforming load balancing.

There is further disclosed an example, wherein the exclude list is anaccess control list.

There is further disclosed an example, wherein the exclude listcomprises at least an IP address, port, and protocol.

There is further disclosed an example, further comprising a userinterface for enabling a user to configure the exclude list.

There is further disclosed an example, wherein the user interfaceincludes a command line interface.

There is further disclosed an example, wherein the exclude list providesa route map deny sequence having a match and no set action.

There is further disclosed an example, wherein the exclude list ismatched before any list for load balanced traffic.

There is further disclosed an example, wherein the exclude listcomprises a whitelist of load balanced traffic.

There is further disclosed an example, wherein the load balancing engineis further operable for receiving a plurality of exclude lists, anddirecting network packets without load balancing to network nodesidentified by the plurality of exclude lists.

There is further disclosed by way of example, one or more tangible,non-transitory computer-readable storage mediums having stored thereonexecutable instructions for providing a load-balanced switching engine,operable for: load balancing at least some incoming network traffic;receiving an exclude list identifying a network node excluded from loadbalancing; identifying a network packet directed to the network nodeexcluded from load balancing; and directing the network packet to thenetwork node excluded from load balancing without performing loadbalancing.

There is further disclosed an example, wherein the exclude list is anaccess control list.

There is further disclosed an example, wherein the exclude listcomprises at least an IP address, port, and protocol.

There is further disclosed an example, further comprising a userinterface for enabling a user to configure the exclude list.

There is further disclosed an example, wherein the exclude list providesa route map deny sequence having a match and no set action.

There is further disclosed an example, wherein the exclude list ismatched before any list for load balanced traffic.

There is further disclosed by way of example, a computer-implementedmethod of providing load-balanced network switching, comprising: loadbalancing at least some incoming network traffic; receiving an excludelist identifying a network node excluded from load balancing;identifying a network packet directed to the network node excluded fromload balancing; and directing the network packet to the network nodeexcluded from load balancing without performing load balancing.

There is further disclosed an example, wherein the exclude list is anaccess control list.

There is further disclosed an example, wherein the exclude listcomprises at least an IP address, port, and protocol.

There is further disclosed an example, wherein the exclude list providesa route map deny sequence having a match and no set action.

There is further disclosed an example, wherein the exclude list ismatched before any list for load balanced traffic.

There is further disclosed an example of one or more tangiblenon-transitory computer-readable storage mediums having stored thereonexecutable instructions for providing an engine or for performing amethod as disclosed in any of the preceding claims.

There is further disclosed an example of a method comprising any or allof the operations as disclosed in any of the preceding examples.

There is further disclosed an apparatus comprising means forimplementing any of the preceding examples.

There is further disclosed an example wherein the means comprise acomputing system.

There is further disclosed an example wherein the means comprise aprocessor and a memory.

There is further disclosed an example wherein the means comprise aprogrammable hardware device such as an ASIC or FPGA.

Note that in this Specification, references to various features (e.g.,elements, structures, modules, components, steps, operations,characteristics, etc.) included in “one embodiment”, “exampleembodiment”, “an embodiment”, “another embodiment”, “some embodiments”,“various embodiments”, “other embodiments”, “alternative embodiment”,and the like are intended to mean that any such features are included inone or more embodiments of the present disclosure, but may or may notnecessarily be combined in the same embodiments. Furthermore, the words“optimize,” “optimization,” and related terms are terms of art thatrefer to improvements in speed and/or efficiency of a specified outcomeand do not purport to indicate that a process for achieving thespecified outcome has achieved, or is capable of achieving, an “optimal”or perfectly speedy/perfectly efficient state.

In example implementations, at least some portions of the activitiesoutlined herein may be implemented in software in, for example,provisioned in service appliance 224 and/or switch 190 (e.g., throughvarious modules, algorithms, processes, etc.). In some embodiments, oneor more of these features may be implemented in hardware, providedexternal to these elements, or consolidated in any appropriate manner toachieve the intended functionality. Service appliance 224 and/or switch190 may include software (or reciprocating software) that can coordinatein order to achieve the operations as outlined herein. In still otherembodiments, these elements may include any suitable algorithms,hardware, software, components, modules, interfaces, or objects thatfacilitate the operations thereof.

Furthermore, switch 190 and service appliance 224 described and shownherein (and/or their associated structures) may also include suitableinterfaces for receiving, transmitting, and/or otherwise communicatingdata or information in a network environment. Additionally, some of theprocessors and memories associated with the various network elements maybe removed, or otherwise consolidated such that a single processor and asingle memory location are responsible for certain activities. In ageneral sense, the arrangements depicted in the FIGURES may be morelogical in their representations, whereas a physical architecture mayinclude various permutations, combinations, and/or hybrids of theseelements. It is imperative to note that countless possible designconfigurations can be used to achieve the operational objectivesoutlined here. Accordingly, the associated infrastructure has a myriadof substitute arrangements, design choices, device possibilities,hardware configurations, software implementations, equipment options,etc.

In some of example embodiments, one or more memories (e.g., memory 392,memory 388) can store data used for the operations described herein.This includes the memory being able to store instructions (e.g., as partof logic, software, code, etc.) that are executed to carry out theactivities described in this Specification. A processor can execute anytype of instructions associated with the data to achieve the operationsdetailed herein in this Specification. In one example, processors 386and processor 390 could transform an element or an article (e.g., data)from one state or thing to another state or thing. In another example,the activities outlined herein may be implemented with fixed logic orprogrammable logic (e.g., software/computer instructions executed by aprocessor) and the elements identified herein could be some type of aprogrammable processor, programmable digital logic (e.g., a fieldprogrammable gate array (FPGA), an erasable programmable read onlymemory (EPROM), an electrically erasable programmable read only memory(EEPROM)), an ASIC that includes digital logic, software, code,electronic instructions, flash memory, optical disks, CD-ROMs, DVD ROMs,magnetic or optical cards, other types of machine-readable mediumssuitable for storing electronic instructions, or any suitablecombination thereof.

In operation, components in system 110 can include one or more memoryelements (e.g., memory 388, memory 392) for storing information to beused in achieving operations as outlined herein. These devices mayfurther keep information in any suitable type of non-transitory storagemedium (e.g., random access memory (RAM), read only memory (ROM), fieldprogrammable gate array (FPGA), erasable programmable read only memory(EPROM), electrically erasable programmable ROM (EEPROM), etc.),software, hardware, or in any other suitable component, device, element,or object where appropriate and based on particular needs. Theinformation being tracked, sent, received, or stored in system 110 couldbe provided in any database, register, table, cache, queue, controllist, or storage structure, based on particular needs andimplementations, all of which could be referenced in any suitabletimeframe. Any of the memory items discussed herein should be construedas being encompassed within the broad term ‘memory.’ Similarly, any ofthe potential processing elements, modules, and machines described inthis Specification should be construed as being encompassed within thebroad term ‘processor.’

It is also important to note that the operations and steps describedwith reference to the preceding FIGURES illustrate only some of thepossible scenarios that may be executed by, or within, the system. Someof these operations may be deleted or removed where appropriate, orthese steps may be modified or changed considerably without departingfrom the scope of the discussed concepts. In addition, the timing ofthese operations may be altered considerably and still achieve theresults taught in this disclosure. The preceding operational flows havebeen offered for purposes of example and discussion. Substantialflexibility is provided by the system in that any suitable arrangements,chronologies, configurations, and timing mechanisms may be providedwithout departing from the teachings of the discussed concepts.

Although the present disclosure has been described in detail withreference to particular arrangements and configurations, these exampleconfigurations and arrangements may be changed significantly withoutdeparting from the scope of the present disclosure. For example,although the present disclosure has been described with reference toparticular communication exchanges involving certain network access,formatting, and protocols, system 110 may be applicable to otherexchanges, formats, or routing protocols. Moreover, although system 110has been illustrated with reference to particular elements andoperations that facilitate the communication process, these elements,and operations may be replaced by any suitable architecture or processthat achieves the intended functionality of system 110.

Computer program logic implementing all or part of the functionalitydescribed herein is embodied in various forms, including, but in no waylimited to, a source code form, a computer executable form, and variousintermediate forms (for example, forms generated by an assembler,compiler, linker, or locator). In an example, source code includes aseries of computer program instructions implemented in variousprogramming languages, such as an object code, an assembly language, ora high-level language such as OpenCL, Fortran, C, C++, JAVA, or HTML foruse with various operating systems or operating environments. The sourcecode may define and use various data structures and communicationmessages. The source code may be in a computer executable form (e.g.,via an interpreter), or the source code may be converted (e.g., via atranslator, assembler, or compiler) into a computer executable form.

In one example embodiment, any number of electrical circuits of theFIGURES may be implemented on a board of an associated electronicdevice. The board can be a general circuit board that can hold variouscomponents of the internal electronic system of the electronic deviceand, further, provide connectors for other peripherals. Morespecifically, the board can provide the electrical connections by whichthe other components of the system can communicate electrically. Anysuitable processors (inclusive of digital signal processors,microprocessors, supporting chipsets, etc.), memory elements, etc. canbe suitably coupled to the board based on particular configurationneeds, processing demands, computer designs, etc. Other components suchas external storage, additional sensors, controllers for audio/videodisplay, and peripheral devices may be attached to the board as plug-incards, via cables, or integrated into the board itself. In anotherexample embodiment, the electrical circuits of the FIGURES may beimplemented as stand-alone modules (e.g., a device with associatedcomponents and circuitry configured to perform a specific application orfunction) or implemented as plug-in modules into application specifichardware of electronic devices.

Note that with the numerous examples provided herein, interaction may bedescribed in terms of two, three, four, or more electrical components.However, this has been done for purposes of clarity and example only. Itshould be appreciated that the system can be consolidated in anysuitable manner. Along similar design alternatives, any of theillustrated components, modules, and elements of the FIGURES may becombined in various possible configurations, all of which are clearlywithin the broad scope of this Specification. In certain cases, it maybe easier to describe one or more of the functionalities of a given setof flows by only referencing a limited number of electrical elements. Itshould be appreciated that the electrical circuits of the FIGURES andits teachings are readily scalable and can accommodate a large number ofcomponents, as well as more complicated/sophisticated arrangements andconfigurations. Accordingly, the examples provided should not limit thescope or inhibit the broad teachings of the electrical circuits aspotentially applied to a myriad of other architectures.

Numerous other changes, substitutions, variations, alterations, andmodifications may be ascertained to one skilled in the art and it isintended that the present disclosure encompass all such changes,substitutions, variations, alterations, and modifications as fallingwithin the scope of the appended claims. In order to assist the UnitedStates Patent and Trademark Office (USPTO) and, additionally, anyreaders of any patent issued on this application in interpreting theclaims appended hereto, Applicant wishes to note that the Applicant: (a)does not intend any of the appended claims to invoke paragraph six (6)of 35 U.S.C. section 112 as it exists on the date of the filing hereofunless the words “means for” or “steps for” are specifically used in theparticular claims; and (b) does not intend, by any statement in thespecification, to limit this disclosure in any way that is not otherwisereflected in the appended claims.

What is claimed is:
 1. A computing apparatus for providing load-balancedswitching, comprising: a switching network, comprising an ingressinterface and a plurality of egress interfaces; one or more logicelements operable for providing network switching comprising switchingincoming traffic from the ingress interface to the plurality of egressinterfaces; and one or more logic elements on a common hardware platformwith the switching network and the one or more logic elements operablefor providing network switching, comprising a load balancing engineoperable for: load balancing at least some of the incoming networktraffic according to a load balancing algorithm; receiving a whitelistof load balancing traffic; receiving a network packet directed to anetwork node; determining whether the network packet or the network nodeis on the whitelist; and if the network packet or the network node isnot on the whitelist, directing the network packet to the network nodewithout performing load balancing.
 2. The computing apparatus of claim1, wherein the load balancing engine is further operable for receivingan exclude list identifying a network node excluded from load balancing.3. The computing apparatus of claim 2, wherein the exclude listcomprises at least an IP address, port, and protocol.
 4. The computingapparatus of claim 2, further comprising a user interface for enabling auser to configure the exclude list.
 5. The computing apparatus of claim4, wherein the user interface includes a command line interface.
 6. Thecomputing apparatus of claim 2, wherein the exclude list provides aroute map deny sequence having a match and no set action.
 7. Thecomputing apparatus of claim 2, wherein the exclude list is matchedbefore any list for load balanced traffic.
 8. The computing apparatus ofclaim 2, wherein the exclude list is an access control list.
 9. Thecomputing apparatus of claim 2, wherein the exclude list includes atleast an exclude rule indicating that the load balancing engine is toforward a first network packet to a destination address without furtherprocessing the first network packet.
 10. One or more tangible,non-transitory computer-readable storage mediums having stored thereonexecutable instructions for providing a load-balanced switching engine,operable for: load balancing at least some of the incoming networktraffic according to a load balancing algorithm; receiving a whitelistof load balancing traffic; receiving a network packet directed to anetwork node; determining whether the network packet or the network nodeis on the whitelist; and if the network packet or the network node isnot on the whitelist, directing the network packet to the network nodewithout performing load balancing.
 11. The one or more tangible,non-transitory computer readable mediums of claim 10, wherein theinstructions are further operable for receiving an exclude listidentifying a network node excluded from load balancing.
 12. The one ormore tangible, non-transitory computer-readable mediums of claim 11,wherein the exclude list comprises at least an IP address, port, andprotocol.
 13. The one or more tangible, non-transitory computer-readablemediums of claim 11, further comprising a user interface for enabling auser to configure the exclude list.
 14. The one or more tangible,non-transitory computer-readable mediums of claim 11, wherein theexclude list provides a route map deny sequence having a match and noset action.
 15. The one or more tangible, non-transitorycomputer-readable mediums of claim 11, wherein the exclude list ismatched before any list for load balanced traffic.
 16. Acomputer-implemented method of providing load-balanced networkswitching, comprising: load balancing at least some of the incomingnetwork traffic according to a load balancing algorithm; receiving awhitelist of load balancing traffic; receiving a network packet directedto a network node; determining whether the network packet or the networknode is on the whitelist; and if the network packet or the network nodeis not on the whitelist, directing the network packet to the networknode without performing load balancing.
 17. The method of claim 16,further comprising receiving an exclude list identifying a network nodeexcluded from load balancing.
 18. The method of claim 17, wherein theexclude list comprises at least an IP address, port, and protocol. 19.The method of claim 17, wherein the exclude list provides a route mapdeny sequence having a match and no set action.
 20. The method of claim17, wherein the exclude list is matched before any list for loadbalanced traffic.